All posts by Thomas

Technology

Kinect it!

At first we had to set up the Kinect with Ubuntu. The tutorial from www.kdab.com came in very handy for a first try. Later we decided to use the openframeworks toolkits. It is an awesome collection of libraries and it contains the “ofxKinect” addon, which comes with some basic examples fitting perfectly for our purposes. Furthermore it’s written in C++ and it is open source.
We used the basic example for ofxKinect and adapted it.

first_try
Example of ofxKinect Addon

For our design we need to track the actors on the stage in a defined area (in front of the projection). Therefore we decided to mount the Kinect to the ceiling, to leave the stage open to every possible design and keep the view from the audience to the stage clear.
To track just the actors we implemented a possibility to define the minimum rectangle one can draw around a blob the actor builds. This way we can set the height and width of this rectangle so it won’t track incorrectly the screen or a prop on the stage. It’s not working perfectly save now, because if a person touches an element of the stage it’s blob connects with the contour of the element. Then the new blob is mistakenly tracked as an actor and the tracked values are wrong.

mistaken_blob
A wrong tracked blob

The example came with the possibility to define the nearest and farthest threshold the Kinect is detecting. Of course we kept this feature and made it, with the others too, easy accessible through a graphical user interface, build with the help of the addon “ofxGUI”.
For the feature to draw with hands into the projection we used the possibility of Kinect to get the depth of every pixel the picture holds. We can set a range in which the height (we’re still beneath the ceiling) of the closest point to the projection plane (the upper range of the screen) of the blob is measured. Because humans tend to stretch their arms for drawing gestures, it was the easiest way to assume that the nearest point is the crucial and important one.

A drawing scene
A drawing scene

For the task of visualisation and projection it seemed to be good to use processing. It is easy to handle, has a lot of examples to mess around with and most designers like it. To use the data Kinect has tracked in processing , we decided to send messages containing our data via OSC. OSC is also easy to set up and you can design your messages at your wish. Right now we just have to send some float values, like the centre values of the actor and the x-/y-value of the closest point the actor gives, but of course we can send a lot more data if we want to. Because we use OSC for sending messages we are also able to set up the tracking on one laptop and give the projection task to another, faster one.
The processing sketches are basically drawing rectangles or ellipses on a beautifully designed background-image.

Storyboard – Kinect Use in “Dusk”

Kinect, Shadow and Light – Design

Literature

Oskar Schlemmer – The Triadic Ballet and the Bauhaus stage

Oskar Schlemmer- Das tradische Ballett und die Bauhausbühne, by Dirk Scheper, published in: Schriftreihe der akademischen Künste Band 20

The Bauhaus stage was established in 1920 by Oskar Schlemmer and was an unique scene to explore the relations of body and space. It was a place to create a certain restatement of the elements of designing and arranging the stage. Schlemmer himself was dealing with form, colour, sound, motion, light and the tension between person and space. He was the first person which looked closer at the effects of playing with the listed elements.

With help of shapes and forms it is possible to define the space on stage and contrasting  it. The use of colour as well as the use of forms generates emotions. Schlemmer stated, that every person has its own inner circle of colour and so its own preferences and aversions. The effect of light can be used to bound the space on stage and to create smaller or larger areas and regions.

Schlemmer designed a totally different style of costumes. Costumes that were no longer just for a most realistic appearance of actors. They were created for an emotional effect on the audience. Some costumes limited the movement of its wearer and some of them made only a backward movement possible. Schlemmer suggested to experiment and play around with the use of different forms  and shapes on costumes. Most of the costumes were not easy or comfortable to wear, but still today actors feel honoured if they get the possibility  to wear them.

The use of sound and music was mostly limited to a piano and an ambient style. The use of voice or dialogues was not important for Schlemmers ballet.

For our exploration of  interactive theatre it is good to get an awareness of different effects of all elements on the stage.  Unfortunately we do not have the capabilities to explore the impact of light, sound, colours etc. on a real  stage, so it is good to keep in mind, that every shape, every colour, every tone creates an specific but different emotion to the audience.